because of a ceiling joist being dead center in a room, i am installing two center speakers. my question is do i run them series or parallel to present a smaller resistance back to the receiver.
thanks,

thurs

can you do in walls? Cut and head off.

no preconstruction brackets are in ceiling. customer wanted them there.
they are one bay apart. i just need to balance them and present a 6 ohm drain to the amp.

Let's supposed that your speakers are 8 Ohm. If you put them in parallel your amp will see 4 Ohm but if you put them in series your amp will see 16 Ohm.

Asasuming you have 8 ohm speakers...........

In series would be 16 ohms......8+8=16

In Parallel would be 4 ohms.....8x8/8+8 = 64/16 = 4

Many speakers that have an 8 ohm rating actually test lower (6 ohms or so) So, in this scenario, series would probably be better, and in fact, 3 Ohm in parralel might be a problem for the amplifier. Another Q might be how much headroom your amplifier has.

Whatever you do you don't want to get too close to 2 Ohm.

Can you series speakers that have a built in crossover, isn't that a problem?

Speakers with built in crossovers include the crossover's impedance withing the Speaker's impedance. Impedance is the resistance of that component to alternating current.The total impedance of a component has three components resistance + inductive impedance + capacitive inpedance.

Generally speaking, it's not good practice to series-connect speakers, because the impedances can interact. However, it is acceptable if the two speakers are identical.

Run the + wire to one speaker's red, and the - wire to the other speaker's black, and then connect the remaining two terminals together.

Another but more costly option would be to run the line out of the center channel into a two channel power amplifier and attenuate accordingly

I understand how to series a speaker. But Elan tech support told one of my fellow techs not to do it because the speakers crossover would affect the sound of the 2nd speaker. Is this true?

is changing the framing totally out of the question?

If the speakers only had a 6 db crossover, series would work,(you may have to replace the cap with a different value). However, if the crossover is 12 db or higher (with or without eq) it would indeed change several parameters (The crossovers would not work as designed).
If you must use 2 speakers in this install, go for the external amp if the receiver cannot handle the 3ohm load.

Which speaker would be the "second" speaker? Two identical loads in series will split the voltage and current between them equally. Having reactive components doesn't change that.

There's no reason that having a second order (or higher) crossover should affect whether series wiring will work. The internal pathways are irrelevant

The two speakers as wholes would be connected in series. What matters is the overall impedance curve; as long as the speakers are identical, two will function (on twice the voltage) just as one would.